A so-called side airbag, also referred to as a curtain airbag or window airbag, unfolds essentially on a vehicle interior in the event of an accident, in order to protect the head and thorax area of occupants in particular during a side impact or a rollover of the vehicle and to prevent the head of an occupant from projecting outward unprotected through an open side window during accident or the occupants from being thrown out of the vehicle cabin. Such airbags are typically housed folded in the area of a normally curved roof pillar, so that their installation length is greater than the linear or shortest connection between lower fastening points. Therefore, they must be stretched out in the unfolded state, in order to fulfill their safety functions described above.
For this purpose, U.S. Pat. No. 6,824,164 B2 proposes a belt tensioner and DE 1908 24 601 C2 and DE 100 49 389 B4 propose elastic tensioning bands, which have complex designs and/or are limited in their effect.
A side airbag is known from WO 2006/060539 A1 and U.S. Pat. No. 6,695,341 B2, which has a fillable hose as the tensioning means, which is connected in WO 2006/060539 A1 in a lower area and in U.S. Pat. No. 6,695,341 B2 in a middle area to an airbag of the side airbag. As a result of the radial expansion upon filling of this hose, its axial length shortens between fastening points, in order to stretch out the unfolded airbag.
The stretching force of such essentially one-dimensional tensioning means is limited, however. In addition, such known side airbags, whose airbag is typically fastened below a lateral roof frame, only offers little protection in the event of a collision of the head of the occupant with the roof-side vehicle body structure, as may occur in particular during rollovers, for which the side airbag is particularly conceived.
An airbag also usable as a side airbag is known from DE 297 09 389 U1, in which an annular chamber is implemented integrally with the airbag by seam strips, which only communicates via throttled passages with the internal volume of the airbag and is to limit its expansion in particular. Accordingly, the airbag is not stretched out through the annular chamber.
At least one object of the present invention is to improve a side airbag. In addition, other objects, desirable features, and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.